title: Transcriptional regulation of protein kinase C by 1,25-dihydroxyvitamin D3 in HL-60 cells.
abstract: Vitamin D3 treatment of the human promyelocytic cell line, HL-60, is accompanied by an increase in phorbol ester receptor number (Martell, R. E., Simpson, R. U., and Taylor, J. M. (1987) J. Biol. Chem. 262, 5570-5575). In this study, the mechanism and significance of vitamin D3-induced changes in protein kinase C levels were investigated. Treatment of HL-60 cells with 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) resulted in a 2-3-fold increase in phorbol dibutyrate binding at 24 h. This was accompanied by a 4.2-fold increase in steady state mRNA levels for the beta isoenzyme of protein kinase C and by a 3.8-fold increase in its transcriptional rate as determined from nuclear run-off studies. Protein kinase C alpha mRNA, which was approximately 15% of the beta isoenzyme levels, showed similar increases in mRNA and transcriptional rates in response to 1,25-(OH)2D3. Protein kinase C gamma mRNA was not detected. The increases in protein kinase C levels were accompanied by increases in activation of the enzyme by phorbol esters. More importantly, 1,25-(OH)2D3 caused a 1.5-2.0-fold increase in the endogenous phosphorylation of protein kinase C substrates independent of exogenous activators or endogenous formation of diacylglycerol. This is the first report of transcriptional activation of protein kinase C. This mechanism of up-regulation of protein kinase C may explain the increased activity of protein kinase C in vitamin D3-treated HL-60 cells, and may constitute an important mechanism for the long term modulation of the protein kinase C pathway of cell regulation independent of diacylglycerol generation.
authors.affiliation: Department of Medicine, Duke University, Durham, North Carolina 27710.
authors.forename: L M
authors.initials: LM
authors.lastname: Obeid
authors.forename: T
authors.initials: T
authors.lastname: Okazaki
authors.forename: L A
authors.initials: LA
authors.lastname: Karolak
authors.forename: Y A
authors.initials: YA
authors.lastname: Hannun
mesh_terms: D029742:Caenorhabditis elegans Proteins; D002117:Calcitriol / Q000494:pharmacology*; D002352:Carrier Proteins; D002460:Cell Line; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D005796:Genes / Q000187:drug effects; D006801:Humans; D007700:Kinetics; D015473:Leukemia, Promyelocytic, Acute; D015240:Phorbol 12,13-Dibutyrate / Q000378:metabolism; D011493:Protein Kinase C / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D011955:Receptors, Drug / Q000187:drug effects / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects*; D014407:Tumor Cells, Cultured / Q000201:enzymology
chemical_list: D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D012333:RNA, Messenger; D011955:Receptors, Drug; C083141:phorbol ester binding protein; C027776:phorbol ester receptor; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C; D002117:Calcitriol; D013755:Tetradecanoylphorbol Acetate